Since a pharmaceutical preparation containing a drug having disagreeable taste, such as a bitter taste, generates the disagreeable taste when orally administered such a preparation is administered, in the dosage form of sugar-coated tablets, film-coated tablets, capsules or the like. On the other hand, because of a great demand for granular compositions which are convenient for preparation of pharmaceuticals, such as powders, fine granules, granules and the like, attempts have been made to suppress bitter tastes in these compositions. A typical example of such attempts may be a process for the production of a powder composition or the like in which a drug is dispersed in a melted waxy solid material having a melting point of from 40.degree. to 100.degree. C., the resulting mixture is solidified by jetting it from an exhaust nozzle or cooling it as it is, and then the solidified product is pulverized. However, since the property of drug release is not taken into consideration, the composition obtained by such a process cannot release the drug sufficiently in the digestive organs in spite of its excellent masking effect, thus decreasing bioavailability of the drug.
Such a problem may be resolved by blending a water soluble substance such as polyethylene glycol or a sucrose fatty acid ester having high HLB, but there is another problem that such a water soluble substance cannot be mixed uniformly with a waxy solid material in a melted state. Also, blending of water soluble excipients such as lactose, mannitol and the like is hardly effective in resolving the problem described above.
JP-A-54-95719 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses that fine granules obtained by melting a composition consisting of hardened oil, macrogol, and optionally a surfactant, suspending tiaramide hydrochloride as a principal bitter drug in the melted composition and then spray-solidifying the resulting suspension can suppress the bitter taste without reducing releasing of the principal agent. However, releasing ratio of the drug from the fine granules after 100 minutes is about 55%, and the releasing of the orally administered principal drug in the stomach is not satisfactory.